Biological clock regulation of blood pressure

Cardiovascular and cerebrovascular diseases (CVDs) are the leading cause of death worldwide. The global annual death rate from CVD is increasing annually. Hypertension is the most readily modifiable risk factor for CVD; therefore, a clear understanding of the endogenous and exogenous factors influencing hypertension is needed to reduce the incidence of CVD. Abnormal blood pressure is the key factor that directly affects hypertension, and its diurnal fluctuation is one of the most commonly and thoroughly studied physiological rhythms in humans. Abnormal circadian rhythms due to elevated blood pressure at night are considered to be more effective and independent predictors of CVD than abnormal blood pressure values are, and the mortality rate is relatively higher in CVD patients with abnormal blood pressure rhythms. At present, nocturnal hypertension is highly prevalent in the Chinese population and other Asian populations, but many research gaps exist in with regard to the pathogenesis and treatment. Twenty-four-hour ambulatory blood pressure (BP) monitoring is currently the gold standard for the clinical diagnosis of blood pressure circadian rhythm disorders, but routine office or home BP measurement is still the measurement method preferred by the public. The popularity of dynamic monitoring technology is limited, resulting in a large number of patients who are not diagnosed in a timely manner and are consequently at high risk for CVD. The importance of and potential risks associated with abnormal blood pressure circadian rhythms are ignored by the public. On the basis of the latest progress in research, this paper summarizes the process by which biorhythms develop and their specific regulatory mechanism for the first time and then introduces various types of diurnal blood pressure fluctuations and their correlation with diseases. In particular, the harmful effects of nocturnal hypertension caused by an abnormal increase in nocturnal blood pressure, specifically the contributions to cardiovascular and cerebrovascular diseases, are emphasized, and the current gaps in and status of research are discussed. The comprehensive factors influencing blood pressure rhythms are then summarized, and the cross-talk mechanism between the biological clock and blood pressure rhythms are summarized with regard to clock genes, the timing of meals, the performance of shift work, immune factors, intestinal flora, genetics, and diet (high salt). Finally, the status of research on and clinical application of chronotherapy for hypertension generated by circadian rhythms are discussed. The aim of this study is to explore the harm caused by diseases resulting from disturbances in blood pressure rhythms, enrich the understanding of CVD pathogenesis, and provide a theoretical basis for reducing the increased risk of CVD.